Amphiasterins: a new family of cytotoxic metabolites from the marine sponge Plakortis quasiamphiaster

A new family of marine metabolites, named amphiasterins (1–17), was isolated from the marine sponge Plakortis quasiamphiaster. They can be divided in five structurally homogeneous groups, whose components differ only in the length and/or in the unsaturation degree of the alkyl side chain. The structures of these compounds were elucidated by spectroscopic data.